U.S. patent number 5,665,330 [Application Number 08/385,502] was granted by the patent office on 1997-09-09 for dual purposed diagnostic/therapeutic agent having a tri-iodinated benzoyl group linked to a coumarin.
This patent grant is currently assigned to Nano Systems LLC. Invention is credited to Sui-Ming Wong.
United States Patent |
5,665,330 |
Wong |
September 9, 1997 |
Dual purposed diagnostic/therapeutic agent having a tri-iodinated
benzoyl group linked to a coumarin
Abstract
The invention provides a novel compound having the structure
##STR1## wherein R is alkyl and R1, R2, R3 and R4 are each
independently OCH3, H or I and n is 0 or 1 and m is 0 or 1. The
compound is useful in a method of treating mammals either
therapeutically or imaging mammals for diagnostic purposes. Useful
therapeutic areas are in treating lymph nodes and tumors and
diagnostic treatment is applicable to lymph nodes, tumors and in
blood pool imaging. It is particularly advantageous to link an
insoluble carrier molecule with a therapeutic or imaging agent to
form the structure above. This makes the conjugate insoluble and
thus amenable to forming nanoparticles.
Inventors: |
Wong; Sui-Ming (Collegeville,
PA) |
Assignee: |
Nano Systems LLC (Collegeville,
PA)
|
Family
ID: |
23521650 |
Appl.
No.: |
08/385,502 |
Filed: |
February 8, 1995 |
Current U.S.
Class: |
424/9.44;
514/454; 514/457; 549/289; 549/280 |
Current CPC
Class: |
C07D
311/16 (20130101); A61K 49/0485 (20130101); A61K
49/0438 (20130101) |
Current International
Class: |
A61K
49/04 (20060101); C07D 311/16 (20060101); C07D
311/00 (20060101); A61K 049/04 (); A01N 043/16 ();
C07D 311/78 () |
Field of
Search: |
;424/9.44,9.4,9.45,9.451,9.453,9.455 ;514/454,457 ;549/280,289 |
References Cited
[Referenced By]
U.S. Patent Documents
|
|
|
5100914 |
March 1992 |
Redenbach-Mueller et al. |
5141734 |
August 1992 |
Misra et al. |
5145684 |
September 1992 |
Liversidge et al. |
|
Primary Examiner: Hollinden; Gary E.
Assistant Examiner: Hartley; Michael G.
Attorney, Agent or Firm: Rudman & Associates
Claims
I claim:
1. A compound having the structure ##STR7## wherein R is alkyl
comprising from 1 to 6 carbon atoms;
R.sup.1, R.sup.2, R.sup.3, and R.sup.4 is each independently
OCH.sub.3, H or I
n is 0 or 1; and
m is 0 or 1.
2. The compound of claim 1 wherein;
R is CH.sub.3 ;
R.sup.1 is hydrogen;
R.sup.2 is OCH.sub.3 or hydrogen;
R.sup.3 is OCH.sub.3 ; and
R.sup.4 is hydrogen.
3. The compound of claim 1 wherein n is 0.
4. The compound of claim 1 wherein n is 1.
5. A method of diagnosing a mammal, wherein the method comprises
administering to the mammal a nanoparticulate formulation
comprising the compound of claim 1 and subjecting said mammal to a
CT X-ray imaging procedure.
6. The method of claim 5 wherein lymph nodes are imaged.
7. The method of claim 5 wherein a tumor is imaged.
8. The method of claim 5 wherein the mammal's blood pool is
imaged.
9. A nanoparticulate formulation comprising the compound of claim
1.
10. A nanoparticulate formulation comprising the compound of claim
2.
11. A nanoparticulate formulation comprising the compound of claim
3.
12. A nanoparticulate formulation comprising the compound of claim
4.
13. A compound of the structure ##STR8##
14. A compound of the structure ##STR9##
Description
FIELD OF THE INVENTION
The present invention relates to novel compounds and their use in
diagnostic imaging of mammals and the potential use in therapy.
These compounds are useful in the treatment and diagnosis of tumor,
lymph nodes and for imaging of blood pools.
BACKGROUND OF THE INVENTION
Compounds useful for diagnostic imaging and therapeutic treatment
of mammals are numerous in the art. Most of these compounds are
water soluble and hence, not amenable to use of nanoparticles such
as described in U.S. Pat. No. 5,145,684 of Liversidge et al.
U.S. Pat. No. 5,141,734 describes a method of targeting an x-ray
control agent to a specific population of cells or organs.
Targeting may be accomplished by forming a complex of a
radiographic label with an RME-type saccharide capable of
interacting with a cell receptor. The radiopaque label may include
a polyiodinated aromatic group.
U.S. Pat. No. 5,100,914 describes arylalkoxycoumarins wherein the
aryl group can be a phenyl ring substituted with halogen. The
coumarins are useful as therapeutic agents for the treatment of CNS
disorders.
SUMMARY OF THE INVENTION
The present invention provides a novel compound having the formula:
##STR2## wherein R1, R2, R3 and R4 are each independently OCH3, H
or I and m is 0 or 1 and n is 0 or 1.
When n and m are 0 the compound is particularly useful as a
diagnostic imaging agent for mammals for lymph nodes, tumors and
blood pool although it is also useful as a therapeutic agent. When
an n and m are one, the compound can be early hydrolyzed by
esterase and thus releasing the diagnostic and the therapeutic
units as evidenced by our enzymatic hydrolysis studies of a series
of diatrizoate analogues.
The invention also comprises a method of treating mammals
therapeutically with compositions comprising the above compound and
a method of diagnostically imaging mammals with compositions
comprising the above compound. The compositions are in
nanoparticulate form and should provide excellent
bioavailability.
In view of the above, this invention also comprises a method of
linking an insoluble carrier molecule with a soluble therapeutic or
imaging agent to make the conjugate insoluble and thus amenable to
forming nanoparticles.
In another embodiment of this invention, the functional state of a
body organ is assessed by monitoring the rate of cleavage from the
organ of the product of a carrier molecule and a diagnostic
molecule.
DETAILED DESCRIPTION OF THE INVENTION
The novel compound of the invention has the formula: ##STR3##
wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are each
independently OCH.sub.3, H or I and m is 0 or 1 and n is 0 or 1
and
R is an alkyl comprising from 1 to 6 carbon atoms such as methyl,
ethyl, isopropyl, butyl, pentyl, hexyl and the like.
When n and m are 0, the compound is useful as a therapeutic or
imaging agent. When n and m are 1, the compound can be hydroylized
enzymatically for assessing the functional state of a body
organ.
For treating mammals therapeutically, the therapeutic component can
be any water soluble agent which can form an ester bond with sodium
diatrizoate, such as radiosensitizers, triapazamide or aspirins.
For imaging mammals the imaging component can be any analogues of
diatrizoic acids.
A nanoparticulate composition comprising the compound described
above typically can contain F68, F108, T908, B20-5000, ED-BO-ED
triblock copolymers, PVP, sugar surfactants as stabilizer and PEG
1450, PEG 400; DOSS as a cloud point modifier in sterilized
distilled water or sterilized saline or buffers.
The nanoparticles useful in the practice of this invention can be
prepared according to the methods disclosed in U.S. Pat. No.
5,145,684 and U.S. Pat. No. No. 5,318,767.
Briefly, a method for the preparation of a nanoparticle composition
according to this invention includes the steps of introducing a
diagnostic or therapeutic agent, a liquid medium, grinding media,
and optionally, a surface modifier into a grinding vessel; wet
grinding to reduce the particle size of the agent to less than
about 1000 nm; and separating the particles and the liquid medium
from the grinding vessel and grinding media, for example, by
suction, filtration or evaporation. If the surface modifier is not
present during wet grinding, it can be admixed with the particles
thereafter. The liquid medium, most often water, can serve as the
pharmaceutically acceptable carrier. The method preferably is
carried out under aseptic conditions.
A general procedure for preparing the particles useful in the
practice of this invention follows. The therapeutic or diagnostic
agent selected is synthesized or obtained commercially, coupled
together synthetically to provide water insoluble products, and/or
prepared by techniques known in the art, in a conventional coarse
form. It is preferred, but not essential, that the particle size of
the coarse therapeutic or diagnostic substance selected be less
than about 100 m as determinedby sieve analysis. If the coarse
particle size of that agent is greater than about 100 m, then it is
preferred that the coarse particles of the therapeutic or
diagnostic agent be reduced in size to less than 100 m using a
conventional milling method such as airjet or fragmentation
milling.
The coarse therapeutic/diagnostic agent selected can then be added
to a liquid medium in which it is essentially insoluble to form a
premix. The concentration of the therapeutic or diagnostic agent in
the liquid medium can vary from about 0.1-60%, and preferably is
from 5-30% (w/w). it is preferred, but not essential, that the
surface modifier be present in the premix. The concentration of the
surface modifier can vary from about 0.1 to 90%, and preferably is
1-75%, more preferably 2-50% and most preferably 5-45 by weight
based on the total combined weight of the drug substance and
surface modifier. The apparent viscosity of the premix suspension
is preferably less than about 1000 centipoise.
The premix can be used directly by wet grinding to reduce the
average particle size in the dispersion to less than about 1000 nm.
It is preferred that the premix be used directly when a ball mill
is used for attrition. Alternatively, the therapeutic/diagnostic
agent and, optionally, the surface modifier, can be dispersed in
the liquid medium using suitable agitation, e.g., a roller mill or
a Cowles type mixer, until a homogeneous dispersion is observed in
which there are no large agglomerates visible to the naked eye. It
is preferred that the premix be subjected to such a premilling
dispersion step when a recirculating media mill is used for
attrition.
Wet grinding can take place in any suitable dispersion mill,
including, for example, a ball mill, an attritor mill, a vibratory
mill, a planetary mill and media mills such as a sand mill and a
bead mill. A media mill is preferred due to the relatively shorter
milling time required to provide the intended result, i.e., the
desired reduction in particle size. For media milling, the apparent
viscosity of the premix preferably is from about 100 to about 1000
centipoise. For ball milling, the apparent viscosity of the premix
preferably is from about 1 up to about 100 centipoise. Such ranges
tend to afford an optimal balance between efficient particle
fragmentation and media erosion.
The grinding media for the particle size reduction step can be
selected from rigid media preferably spherical or particulate in
form having an average size less than about 3 mm and, more
preferably less than about 1 mm. Such media desirably can provide
the particles of the invention with shorter processing times and
impart less wear to the milling equipment. The selection of
material for the grinding media is not believed to be critical.
However, media with higher density, e.g., glass (2.6 g/cm3),
zirconium silicate (3.7 g/cm3), and zirconium oxide (5.4 g/cm3),
are generally preferred for more efficient milling. Zirconium
oxide, such as 95% ZrO stabilized with magnesia, zirconium
silicate, and glass grinding media provide particles having levels
of contamination which are believed to be acceptable for the
preparation of therapeutic of diagnostic compositions. However,
other media, such as stainless steel, titania, alumina, and 95% ZrO
stabilized with yttrium, are believed to be useful. In addition,
polymeric media having a density typically from 1 to 2 g/cm3 are
also expected to be useful under certain milling conditions. The
grinding media can be a polymeric media such as described in
European Patent Application No. 600,528.
The attrition time can vary widely and depends primarily upon the
particular wet grinding mill selected. For ball mills, processing
times of up to five days or longer may be required. On the other
hand, processing times of less than 1 day (residence times of about
one minute up to several hours) have provided the desired results
including a high shear media mill.
An important advantage of this invention is that an insoluble
compound can be formulated from a generally water soluble compound
by linking the carrier (which itself can be either a imaging or
therapeutic agent) which is water insoluble with the soluble
therapeutic or imaging agent.
The above compounds are prepared by reacting a ditriazoat material
such as sodium ditriazoate with a coumarin such as sodium methylene
bromo-methoxy-coumarin. The reactions are performed under reflex by
mixing the reagents in suitable solvents such as DMF, DMSO,
methanol, and ethanol in the presence of a weak base such as
calcium carbonate.
Despite the high water solubility of sodium ditriazoate and sodium
methoxy coumarin (>1 mg/ml), WIN 67638 and WIN 67591 are
sparingly soluble in water with solubility less than 0.01
mg/mL.
By water soluble is meant greater than 1 mg/ml.
The compositions of this invention can be administered by a variety
of routes depending on the type of procedure and the anatomical
orientation of this tissue being examined. Suitable administration
routes include intravascular (arterial or venous) administation by
catheter, intravenous injection, rectal administration,
subcutaneous administration, intramuscular administration,
intralesional administration, intrathecal administration,
intracisternal administration, oral administration, administration
via inhalation, administration directly into a body cavity, e.g.,
arthrography, and the like. In addition to preferred applications,
i.e., for blood pool, liver, spleen and lymph node imaging, the
x-ray contrast compositions of this invention are also expected to
be useful as an angiographic contrast media, urographic contrast
media, myelographic contrast media, gastrointestinal contrast
media, cholecystographic and cholangiographic contrast media,
arthrographic contrast media, hysterosalpingographic contrast
media, oral contrast media and bronchographic contrast media.
The dose of the contrast agent to be administered can be selected
according to techniques known to those skilled in the art such that
a sufficient contrast enhancing effect is obtained. Typical doses
can range from 50 to 350 mg of iodine per kilogram of body weight
of the subject for many imaging applications. For some
applications, e.g.,, lymphography, lower doses, e.g., 0.5-20 mg
I/kg, can be effective.
The x-ray contrast composition can contain one or more conventional
additives used to control and/or enhance the properties of the
x-ray contrast agent. For example, thickening agents such as
dextran or human serum albumin, buffers, viscosity regulating
agents, suspending agents, peptizing agents, anti-clotting agents,
mixing agents, and ther drugs and the like can be added. A partial
listing of certain specific additives includes gums, sugars such as
dextran, human serum albumin, gelatin, sodium alginate, agar,
dextrin, pectin and sodium carboxymethyl cellulose. Such additives,
surface active agents, preservatives and the like can be
incorporated into the compositions of the invention.
An important feature of this invention is in functional diagnostic
imaging. Conjugates, as described above, can be used to assess the
functional state of various body organs. By assessing the
functional state of various body organs is meant the enzymatic
activity which can be measuredby the release of diagnostic agent or
the carrier from enzymatic cleavage.
The above is accomplished by monitoring the product of the cleavage
reaction between the carrier molecule and the diagnostic agent. For
example the functional state of the liver can be monitored by the
rate at which a carrier molecule is cleaved from the agent of
interest and hence the rate of clearance of contrast agent from the
organ. Thus, MRI, X-ray, Exterase, Amidase, DNA ASE and others can
be monitored in this fashion.
The following exemplify various aspects of this invention.
EXAMPLES
Example 1 Preparation of WIN 67591
Sodium diatrizoate (2 g), 0.976 g 4-bromomethyl-6, 7
dimethoxy-coumarin and 100 mg calcium carbonate were refluxed in
dimethylformamide (DMF) overnight. The reaction mixture was diluted
with 10 fold volume of water to precipitate WIN 67591. The
precipitate collected by filtration was further purified by
successive washing with solvents, water (3 volume) followed by
mathanol (3 volume) and dichloromethane (3 volume), and drying
under nitrogen to afford 1.5 g WIN 67591.
WIN 67591 appeared as a single peak at retention time 5.19 min. in
the HPLC chromatogram obtained with the following conditions:
Instrument HP1090
Column: RP18 (E. Merck)
Solvent: MeOH: 2% TFA (3:2)
Flow rate: 0.8 ml/min
Monitor UV wavelength: 250 nm.
Its structure was confirmed by NMR, UV and MS spectral analysis to
be ##STR4##
Example 2 Preparation of WIN 67638
Sodium diatrizoate (2 g) was mixed with
4-bromomethyl-7-methoxy-coumarin (0.976 g) in DMR containing 5 mg
of calcium carbonate. The reaction mixture was refluxed for 3 hours
and then dried under nitrogen. Successive washes of the dried
powder with water, methanol and chloroform gave 1.6 g WIN 67638
which appeared as a single spot at a RF value of 0.26 on the TLC
plate developed with a mixture of chloroform: methanol: TA
(10:1:1). The structure of WIN 67638 was confirmed by NMR, UV and
MS spectral analysis to be ##STR5##
Example 3 Preparation of Nanoparticulate WIN 67591 for
Lymphography
0.75 g of WIN 67591, as prepared in Example 1, was added to
approximately 30 ml of 1.1 mm zirconium oxide beads and 10 ml of a
solution which was 2% Tetronic 908 (wt/vol %) and 1% SA9OHCO
(wt/vol %). SA9OHCO is a small sugar surfactant. The suspension was
roller milled in a 60 ml jar at approximately 100 rpm for 7 days.
At the end of this time, the average particle size was determined
to be 192 nm by light scattering using a Zetasizer III. The
suspension was removed from the beads and sent for subcutaneous
injection as a lymphographic agent. CT imaging was carried out
using a GE Model 9800 Instrument. Even though formulated at a low
percent solids (i.e., normal formulations are 15%), this suspension
gave clear enchancement of the axillary nodes of New Zealand White
Rabbits at 4 hours post injection of a single 0.5 ml dose on the
dorsal side of the forepaw. The imaging effect of this 5% solution
of WIN 67591 is similar to that of a 15% formulation of WIN 8883
having the structure ##STR6##
Example 4 Nanoparticulation of WIN 67591 for Blood Pool Imaging
2.85 g of WIN 67591 (19.2%) were added to 30 ml of a solution of
5.2% BASF NF Grade Tetronic 908 (wt/vol %) in sterilized distilled
water and approximately 100 ml of 1.1 mm zirconium silicate beads
in a 250 ml bottle. The bottle was capped and rolled at
approximately 140 rpm for 7 days at which time the average particle
size was determined to be 173 nm. The suspension was separated from
the beads and sent for intravenous injection as a vascular x-ray
contrast agent. New Zealand White rabbits were used for this study
and were injected via the ear vein at a dose of 3 ml/kg. Three
animals were studied for times 5, 15, 30, 60, 120 min. and 24
hours. CT scanning was carried out using a Toshiba Model TCT-900S/x
at the times indicated. The results indicate that this formulation
demonstrates prolonged vascular residence at times beyond 2
hours.
Example 5 Use of WIN 67591 as an Oncological Therapeutic Agent
A nanoparticulate formulation of 5% w/v WIN 67951 in 3%
polyoctylphenol (Tyloxopol) was prepared by ten days roller milling
following the procedures similar to that of Example 9.
The formulation was administered to mice bearing colon 33 tumor by
iv injection. Analysis of the tumor tissue indicated the presence
of WIN 67591 in the tumor tissue as soon as 5 minutes after
injection. The drug concentration reached a maximum of 90 .mu.g/g
of tumor tissue at 6 hours and maintained at a concentration of 60
.mu.g/g of tumor tissue for 42 hours. This concentration in the
tumor tissue exceeds the average therapeutic dosage of
oncologics.
This sustained accumulation of relatively high dose of WIN 67591 in
the tumor tissue suggested the potential of applying this
technology for oncologics, especially for the radiosentizer WIN
59705 and analogues where tumor can be visualized by the diagnostic
agent unit before activation of the radiosentizer.
Example 6 Use of WIN 67591 as a Blood Pool Imaging Agent
A biodistribution study of the treatment of Example 5 was conducted
by iv injections into colon 33 tumor bearing mice at 0.2 ml/animal.
WIN 67591 was found to circulate in the blood for at least one
hour. No dead mice were reported during the 48 hours treatment.
This indicates that WIN 67591 is useful as a blood pool imaging
agent.
Example 7 Nanoformulation of WIN 67591 for Biodistribution
Studies
WIN 69791 as prepared in Example 1 at 5% W/V was formulated with 3%
Tyloxapol by roller milling for ten days following the procedures
similar to that of work example 3 and 4. The average particle size
by PCS was 302 nm. The formulation was administered i.v. to colon
33 bearing mice at 0.2 ml/animal. HPLC analysis of the tumor tissue
indicated prolonged blood circulation of WIN 67591 nanocrystal. As
high as 700 ug (0.7% of the total dosage) WIN 67591 remained
circulating in the blood 1 hour post injection. WIN 67591 was
detected in the tumor tissue as early as 5 minute post injection.
The drug concentration reached a maximum at 90 ug/g of tumor tissue
at 6 hour post injection and maintained at a concentration of 60
ug/g in the tumor tissue for 48 hours.
* * * * *